Surgical stapling instrument incorporating an articulation joint for a firing bar track

ABSTRACT

A surgical stapling and severing instrument particularly suited to endoscopic articulates an end effector by having a general articulation mechanism that converts rotational motion from a handle portion. A firing bar longitudinally translates between the handle portion and the end effector. The firing bar head is thickened in order to present an undistorted cutting edge and engagement features to the opposing jaws of the end effector. The firing bar also advantageously includes a thinned or tapered proximal portion in the form of a strip or band that negotiates the articulation mechanism flexibility. To prevent buckling of the firing bar strip during firing, a pair of support plates adjustably flank the firing bar strip through the articulation mechanism. To advantageously prevent pinching, retaining bars are positioned between the support plates above the firing bar to maintain spacing therethrough.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is related to four co-pending and commonly-ownedapplications filed on even date herewith, the disclosure of each ishereby incorporated by reference in their entirety, these fourapplications being respectively entitled:

(1) “SURGICAL STAPLING INSTRUMENT INCORPORATING A TAPERED FIRING BAR FORINCREASED FLEXIBILITY AROUND THE ARTICULATION JOINT” to Frederick E.Shelton IV, Mike Setser, and Bruce Weisenburgh;

(2) “SURGICAL STAPLING INSTRUMENT HAVING ARTICULATION JOINT SUPPORTPLATES FOR SUPPORTING A FIRING BAR” to Kenneth S. Wales and JosephCharles Heuil;

(3) “SURGICAL INSTRUMENT INCORPORATING AN ARTICULATION MECHANISM HAVINGROTATION ABOUT THE LONGITUDINAL AXIS” to Kenneth S. Wales, Douglas B.Hoffman, Frederick E. Shelton IV, and Jeff Swayze; and

(4) “A SURGICAL INSTRUMENT WITH A LATERAL-MOVING ARTICULATION CONTROL”to Kenneth S. Wales.

FIELD OF THE INVENTION

The present invention relates in general to surgical stapler instrumentsthat are capable of applying lines of staples to tissue while cuttingthe tissue between those staple lines and, more particularly, toimprovements relating to stapler instruments and improvements inprocesses for forming various components of such stapler instrumentsthat include an articulating shaft.

BACKGROUND OF THE INVENTION

Endoscopic surgical instruments are often preferred over traditionalopen surgical devices since a smaller incision tends to reduce thepost-operative recovery time and complications. Consequently,significant development has gone into a range of endoscopic surgicalinstruments that are suitable for precise placement of a distal endeffector at a desired surgical site through a cannula of a trocar. Thesedistal end effectors engage the tissue in a number of ways to achieve adiagnostic or therapeutic effect (e.g., endocutter, grasper, cutter,staplers, clip applier, access device, drug/gene therapy deliverydevice, and energy device using ultrasound, RF, laser, etc.).

Positioning the end effector is constrained by the trocar. Generallythese endoscopic surgical instruments include a long shaft between theend effector and a handle portion manipulated by the clinician, thislong shaft enables insertion to a desired depth and rotation about thelongitudinal axis of the shaft, thereby positioning the end effector toa degree. With judicious placement of the trocar and use of graspers,for instance, through another trocar, often this amount of positioningis sufficient. Surgical stapling and severing instruments, such asdescribed in U.S. Pat. No. 5,465,895, are an example of an endoscopicsurgical instrument that successfully positions an end effector byinsertion and rotation.

Depending upon the nature of the operation, it may be desirable tofurther adjust the positioning of the end effector of an endoscopicsurgical instrument rather than being limited to insertion and rotation.In particular, it is often desirable to orient the end effector at anaxis transverse to the longitudinal axis of the shaft of the instrument.The transverse movement of the end effector relative to the instrumentshaft is conventionally referred to as “articulation”. This articulatedpositioning permits the clinician to more easily engage tissue in someinstances. In addition, articulated positioning advantageously allows anendoscope to be positioned behind the end effector without being blockedby the instrument shaft.

While the aforementioned non-articulating stapling and severinginstruments have great utility and may be successfully employed in manysurgical procedures, it is desirable to enhance their operation with theability to articulate the end effector, thereby giving greater clinicalflexibility in their use. Articulating surgical instruments generallyuse one or more firing bars that move longitudinally within theinstrument shaft and through the articulation joint to fire the staplesfrom the cartridge and to cut the tissue between the innermost staplelines. One common problem with these surgical instruments is control ofthe firing bar through the articulation joint. At the articulationjoint, the end effector is longitudinally spaced away from the shaft sothat the edges of the shaft and end effector don't collide duringarticulation. This gap must be filled with support material or structureto prevent the firing bar from buckling out of the joint when the singleor multiple firing bars is subjected to longitudinal firing loads. Whatis needed is a support structure that guides and supports the single ormultiple firing bars through the articulation joint and bends or curvesas the end effector is articulated.

U.S. Pat. No. 5,673,840 describes a flexible articulation joint that isformed from an elastomeric or plastic material that bends at theflexible joint or “flex neck”. The firing bars are supported and guidedthrough a hollow tube within the flex neck. The flex neck is a portionof the jaw closure mechanism and moves longitudinally relative to theend effector, shaft, and firing bars when the jaws are closed on tissue.The firing bars then move longitudinally within the flex neck as thestaples are fired and tissue is cut.

U.S. Pat. No. 5,797,537 to Allen describes an articulation joint thatpivots around a pin, rather than bends around a flex joint. In thisinstrument, firing bars are supported between a pair of spaced supportplates connected at one end to the shaft and at another end to the endeffector. At least one of those connections is a slidable connection.The support plates extend through the articulation joint adjacent to theflexible drive member in the plane of articulation such that the supportplates bend through the gap in the plane of articulation and theflexible firing bar bends against the support when the tip isarticulated in one direction from its aligned position. U.S. Pat. No.6,330,965 from U.S. Surgical teaches the use of support plates that arefixedly attached to the shaft and slidably attached to the end effector.

Although these known support plates guide a firing bar through anarticulation joint, it is believed that performance may be enhanced. Inparticular, generally support plates and firing bar are sufficientlyflexible in order to allow articulation without an undue amount offorce. In addition, these components are sized and spaced for endoscopicuse through a cannula passageway. Consequently, the plates and firingbar tend to come into contact with one another when articulated,creating binding and friction.

Consequently, a significant need exists for an improved articulationmechanism for a surgical instrument mechanisms that provides enhancedsupport to a firing bar through the articulation joint with reducedfriction.

BRIEF SUMMARY OF THE INVENTION

The invention overcomes the above-noted and other deficiencies of theprior art by providing an articulating surgical instrument that actuatesan end effector with a longitudinally translating firing mechanismadvantageously supported through an articulation mechanism by flankingsupport plates. In order to avoid pinching the firing mechanism as itlongitudinally translates between articulated support plates, aretaining member is inserted between the support plates. The retainingmember assists in providing structural support across the articulationmember as well as spacing the support plates so that friction on thefiring mechanism is reduced.

In one aspect of the invention, a surgical instrument has a handleportion that produces an articulation motion and a firing motion, bothof which are transferred through a shaft to an articulation mechanism.The articulation mechanism responds to the articulation motion to rotatean end effector from the longitudinal axis of the shaft. A firingmechanism responds to the firing motion and is coupled for movementthrough the articulation mechanism and the end effector. A pair ofsupport plates flank the firing mechanism across the articulationmechanism, spaced by a retaining member proximate to the firingmechanism. Thus various types of actuated diagnostic or therapeutic endeffectors may be incorporated into an articulating surgical instrumentwithout buckling at the articulation mechanism, even with high firingforces and reduces component dimensions for endoscopic use.

In another aspect of the invention, a surgical instrument has a handleportion that produces a firing motion, a closing motion, and anarticulation motion, each transferred through a shaft. An articulationmechanism distally coupled to the shaft pivots an end effector inresponse to the articulation motion. The end effector includes anelongate channel coupled to the shaft, an anvil that is pivotallycoupled to the elongate channel and that is responsive to the closingmotion from the shaft. A firing device has a distally presented cuttingedge longitudinally received between the elongate channel and the anvil.An articulation mechanism pivots the elongate channel from the shaft inresponse to the articulation motion. A pair of support plates flank thefiring mechanism across the articulation mechanism, spaced apart by aretaining member. Thereby, an improved stapling and severing instrumentmay incorporate a firing device that withstands high firing loads yetdoes not introduce significantly increased firing forces whenarticulated.

These and other objects and advantages of the present invention shall bemade apparent from the accompanying drawings and the descriptionthereof.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the invention,and, together with the general description of the invention given above,and the detailed description of the embodiments given below, serve toexplain the principles of the present invention.

FIG. 1 is a perspective view of an articulating surgical instrument in anonarticulated position.

FIG. 2 is a perspective view of an articulating surgical instrument inan articulated position.

FIG. 3 is a perspective view of an opened end effector of thearticulating surgical instrument of FIGS. 1-2.

FIG. 4 depicts a side elevation view in section of the end effector ofFIG. 3 of the surgical instrument of FIG. 1, the section generally takenalong lines 4—4 of FIG. 3 to expose portions of a staple cartridge butalso depicting the firing bar along the longitudinal centerline.

FIG. 5 depicts a side elevation view in section of the end effector ofFIG. 4 after the firing bar has fully fired.

FIG. 6 depicts a side elevation view in section of a handle portion of aproximal end of the surgical instrument of FIG. 1 including a rotatingarticulation control.

FIG. 7 depicts a perspective, exploded view of the handle portion of theproximal end of the surgical instrument of FIG. 1.

FIG. 8 depicts a perspective view looking downward, forward and to theright of a distal portion of the handle portion of the surgicalinstrument of FIG. 1 partially cutaway to expose a rotating articulationcontrol mechanism.

FIG. 9 depicts a perspective view looking upward, rearward and to theright of the distal portion of the handle portion of FIG. 7, partiallycutaway to expose the rotating articulation control mechanism and have arotating articulation control knob disassembled.

FIG. 10 depicts a top perspective detail view of a gear tubearticulation mechanism and end effector of the surgical instrument ofFIG. 1 with firing and frame portions removed.

FIG. 11 depicts a perspective, exploded view of an implement portion ofthe surgical instrument of FIG. 1 including a gear tube articulationmechanism.

FIG. 12 depicts a top view in section of the gear tube articulationmechanism of FIG. 10 including support plates for a thinned firing bar.

FIG. 13 depicts a side perspective view of the gear-tube articulationmechanism of FIG. 12 partially cutaway to expose the support plates.

FIG. 14 depicts a perspective, exploded view of the implement portion ofFIG. 11 including retaining bar between the support plates of FIG. 11.

FIG. 15 depicts a perspective view of the support plates, firing bar,and retaining bars of FIG. 14.

DETAILED DESCRIPTION OF THE INVENTION

Turning to the Drawings, wherein like numerals denote like componentsthroughout the several views, FIGS. 1-3 depict a surgical instrument,which in the illustrative embodiment is more particularly a surgicalstapling and severing instrument 10, that is capable of practicing theunique benefits of the present invention. In particular, the surgicalstapling and severing instrument 10 is sized for insertion, in anonarticulated state as depicted in FIG. 1, through a trocar cannulapassageway to a surgical site in a patient for performing a surgicalprocedure. Once an articulation mechanism 11 and a distally attached endeffector 12 are inserted through the cannula passageway, thearticulation mechanism 11 may be remotely articulated, as depicted inFIG. 2, by an articulation control 13. Thereby, the end effector 12 mayreach behind an organ or approach tissue from a desired angle or forother reasons. For instance, a firing mechanism, advantageously depictedas an E-beam firing bar 14 (depicted in FIG. 3), that severs clampedtissue, engages an elongate channel 16 and a pivotally attached anvil18.

The surgical and stapling and severing instrument 10 includes a handleportion 20 connected to an implement portion 22, the latter furthercomprising a shaft 23 distally terminating in the articulating mechanism11 and the end effector 12. The handle portion 20 includes a pistol grip24 toward which a closure trigger 26 is pivotally drawn by the clinicianto cause clamping, or closing, of the anvil 18 toward the elongatechannel 16 of the end effector 12. A firing trigger 28 is fartheroutboard of the closure trigger 26 and is pivotally drawn by theclinician to cause the stapling and severing of clamped tissue in theend effector 12. Thereafter, a release button 30 is depressed to releasethe clamped tissue.

An outmost closure sleeve 32 of the shaft 23 longitudinally translatesin response to the closure trigger 26 to pivotally close the anvil 18.Specifically, a distal portion, or closure ring 33, of the closuresleeve 32 with respect to the articulation mechanism 11 is indirectlysupported by a frame 34 of the implement portion 22 (partially visibleat the articulation mechanism 11). At the articulation mechanism 11, aproximal portion, or closure tube 35, of the closure sleeve 32communicates with the distal portion (closure ring) 33. The frame 34 isflexibly attached to the elongate channel 16 via the articulationmechanism 11, enabling articulation in a single plane. The frame 34 alsolongitudinally slidingly supports a firing drive member 36 thatcommunicates a firing motion from the firing trigger 28 to the firingbar 14. Only the firing bar 14 of the firing drive member 36 is depictedFIG. 3, but the firing drive member 36 is described below further detailwith regard to various versions of a rotationally controlledarticulation mechanism 11.

It will be appreciated that the terms “proximal” and “distal” are usedherein with reference to a clinician gripping a handle of an instrument.Thus, the end effector 12 is distal with respect to the more proximalhandle portion 20. It will be further appreciated that for convenienceand clarity, spatial terms such as “vertical” and “horizontal” are usedherein with respect to the drawings. However, surgical instruments areused in many orientations and positions, and these terms are notintended to be limiting and absolute.

E-BEAM FIRING BAR

FIGS. 3-5 depict the end effector 12 employing the E-beam firing bar 14to perform a number of functions. In FIG. 3, the firing bar 14 isproximally positioned, allowing an unspent staple cartridge 37 to beinstalled into the elongate channel 16. In particular, an upper pin 38of the firing bar 14 resides within a recess, depicted as an anvilpocket 40 allowing the anvil 18 to be repeatedly opened and closed. Withthe end effector closed as depicted in FIG. 4, the firing bar 14 isadvanced in engagement with the anvil 18 by having the upper pin 38enter a longitudinal anvil slot 42. A lower most pin, or firing bar cap44, engaged a lower surface of the elongate channel 16 by having thefiring bar 14 extend through a channel slot 45. A middle pin 46slidingly engages a top surface of the elongate channel 16, cooperatingwith the firing bar cap 44. Thereby, the firing bar 14 affirmativelyspaces the end effector 12 during firing, overcoming pinching that mayoccur with a minimal amount of clamped tissue and overcoming staplemalformation with an excessive amount of clamped tissue.

During firing, a distally presented cutting edge 48 between the upperpin 38 and middle pin 46 of the firing bar enters a proximally presentedvertical slot 49 of the staple cartridge 37, severing tissue clampedbetween the staple cartridge 37 and the anvil 18. As shown in FIG. 4,the middle pin 46 actuates the staple cartridge 37 by entering into afiring slot within the staple cartridge 37, driving a wedge sled 41 intoupward camming contact with staple drivers 43 that in turn drive aplurality of staples 47 out of staple apertures 51 in the staplecartridge 37 into forming contact with staple pockets 53 on an innersurface of the anvil 18. FIG. 5 depicts the firing bar 14 fully distallytranslated after completing severing and stapling tissue.

TWO-AXIS HANDLE

With reference to FIGS. 6-7, the handle portion 20 is comprised of firstand second base sections 50 and 52, which are molded from a polymericmaterial such as a glass-filled polycarbonate. The first base section 50is provided with a plurality of cylindrical-shaped pins 54. The secondbase section 52 includes a plurality of extending members 56, eachhaving a hexagonal-shaped opening 58. The cylindrical-shaped pins 54 arereceived within the hexagonal-shaped openings 58 and are frictionallyheld therein for maintaining the first and second base sections 50 and52 in assembly.

A housing cap 60 has a bore 62 extending completely through it forengaging and rotating the implement portion 22 about its longitudinalaxis. The housing cap 60 includes an inwardly protruding boss 64extending along at least a portion of the bore 62. The protruding boss64 is received within a longitudinal slot 66 formed at a proximalportion of the closure sleeve 32 such that rotation of the housing cap60 effects rotation of the closure sleeve 32. It will be appreciatedthat the boss 64 further extends through frame 34 and into contact witha portion of the firing drive member 36 to effect their rotation aswell. Thus, the end effector 12 (not shown in FIGS. 3-4) rotates withthe housing cap 60.

A proximal end 68 of the frame 34 passes proximally through the housingcap 60 and is provided with a circumferential notch 70 that is engagedby opposing channel securement members 72 extending respectively fromthe base sections 50 and 52. Only the channel securement member 72 ofthe second base section 52 is shown. The channel securement members 72extending from the base sections 50, 52 serve to secure the frame 34 tothe handle portion 20 such that the frame 34 does not movelongitudinally relative to the handle portion 20.

The closure trigger 26 has a handle section 74, a gear segment section76, and an intermediate section 78. A bore 80 extends through theintermediate section 78. A cylindrical support member 82 extending fromthe second base section 52 passes through the bore 80 for pivotallymounting the closure trigger 26 on the handle portion 20. A secondcylindrical support member 83 extending from the second base section 52passes through a bore 81 of firing trigger 28 for pivotally mounting onthe handle portion 20. A hexagonal opening 84 is provided in thecylindrical support member 83 for receiving a securement pin (not shown)extending from the first base section 50.

A closure yoke 86 is housed within the handle portion 20 forreciprocating movement therein and serves to transfer motion from theclosure trigger 26 to the closure sleeve 32. Support members 88extending from the second base section 52 and securement member 72,which extends through a recess 89 in the yoke 86, support the yoke 86within the handle portion 20.

A proximal end 90 of the closure sleeve 32 is provided with a flange 92that is snap-fitted into a receiving recess 94 formed in a distal end 96of the yoke 86. A proximal end 98 of the yoke 86 has a gear rack 100that is engaged by the gear segment section 76 of the closure trigger26. When the closure trigger 26 is moved toward the pistol grip 24 ofthe handle portion 20, the yoke 86 and, hence, the closure sleeve 32move distally, compressing a spring 102 that biases the yoke 86proximally. Distal movement of the closure sleeve 32 effects pivotaltranslation movement of the anvil 18 distally and toward the elongatechannel 16 of the end effector 12 and proximal movement effects closing,as discussed below.

The closure trigger 26 is forward biased to an open position by a frontsurface 130 interacting with an engaging surface 128 of the firingtrigger 28. Clamp first hook 104 that pivots top to rear in the handleportion 20 about a pin 106 restrains movement of the firing trigger 28toward the pistol grip 24 until the closure trigger 26 is clamped to itsclosed position. Hook 104 restrains firing trigger 28 motion by engaginga lockout pin 107 in firing trigger 28. The hook 104 is also in contactwith the closure trigger 26. In particular, a forward projection 108 ofthe hook 104 engages a member 110 on the intermediate section 78 of theclosure trigger 26, the member 110 being outward of the bore 80 towardthe handle section 74. Hook 104 is biased toward contact with member 110of the closure trigger 26 and engagement with lockout pin 107 in firingtrigger 28 by a release spring 112. As the closure trigger 26 isdepressed, the hook 104 is moved top to rear, compressing the releasespring 112 that is captured between a rearward projection 114 on thehook 104 and a forward projection 116 on the release button 30.

As the yoke 86 moves distally in response to proximal movement of theclosure trigger 26, an upper latch arm 118 of the release button 30moves along an upper surface 120 on the yoke 86 until dropping into anupwardly presented recess 122 in a proximal, lower portion of the yoke86. The release spring 112 urges the release button 30 outward, whichpivots the upper latch arm 118 downwardly into engagement with theupwardly presented recess 122, thereby locking the closure trigger 26 ina tissue clamping position.

The latch arm 118 can be moved out of the recess 122 to release theanvil 18 by pushing the release button 30 inward. Specifically, theupper latch arm 118 pivots upward about pin 123 of the second basesection 52. The yoke 86 is then permitted to move proximally in responseto return movement of the closure trigger 26.

A firing trigger return spring 124 is located within the handle portion20 with one end attached to pin 106 of the second base section 52 andthe other end attached to a pin 126 on the firing trigger 28. The firingreturn spring 124 applies a return force to the pin 126 for biasing thefiring trigger 28 in a direction away from the pistol grip 24 of thehandle portion 20. The closure trigger 26 is also biased away frompistol grip 24 by engaging surface 128 of firing trigger 28 biasingfront surface 130 of closure trigger 26.

As the closure trigger 26 is moved toward the pistol grip 24, its frontsurface 130 engages with the engaging surface 128 on the firing trigger28 causing the firing trigger 28 to move to its “firing” position. Whenin its firing position, the firing trigger 28 is located at an angle ofapproximately 45° to the pistol grip 24. After staple firing, the spring124 causes the firing trigger 28 to return to its initial position.During the return movement of the firing trigger 28, its engagingsurface 128 pushes against the front surface 130 of the closure trigger26 causing the closure trigger 26 to return to its initial position. Astop member 132 extends from the second base section 52 to prevent theclosure trigger 26 from rotating beyond its initial position.

The surgical stapling and severing instrument 10 additionally includes areciprocating section 134, a multiplier 136 and a drive member 138. Thereciprocating section 134 comprises a wedge sled, or wedge sled, in theimplement portion 22 (not shown in FIG. 6-7) and a metal drive rod 140.

The drive member 138 includes first and second gear racks 141 and 142. Afirst notch 144 is provided on the drive member 138 intermediate thefirst and second gear racks 141, 142. During return movement of thefiring trigger 28, a tooth 146 on the firing trigger 28 engages with thefirst notch 144 for returning the drive member 138 to its initialposition after staple firing. A second notch 148 is located at aproximal end of the metal drive rod 140 for locking the metal drive rod140 to the upper latch arm 118 of the release button 30 in its unfiredposition.

The multiplier 136 comprises first and second integral pinion gears 150and 152. The first integral pinion gear 150 is engaged with a first gearrack 154 provided on the metal drive rod 140. The second integral piniongear 152 is engaged with the first gear rack 141 on the drive member138. The first integral pinion gear 150 has a first diameter and thesecond integral pinion gear 152 has a second diameter that is smallerthan the first diameter.

ROTATIONAL ARTICULATION CONTROL

With reference to FIGS. 6-9, the handle portion 20 advantageouslyincorporates the articulation control 13 that both rotates the implementportion 22 about the longitudinal axis of the surgical instrument 10 andarticulates the end effector 12 to an angle with the longitudinal axis.A hollow articulation drive tube 200 is concentrically located withinthe closure sleeve 32 and is operably coupled to an actuation lever 202such that rotation of actuation lever 202 rotates tube 200 about thelongitudinal axis and causes perpendicular rotation or articulation ofthe closure ring 250 and end effector 12. This articulation of theclosure ring 250 corresponds to the degree and direction of rotation ofactuator lever 202 viewed and manipulated by the clinician. In theillustrative version, the relationship is one to one, with the degree ofrotation of the actuator lever 202 corresponding to the degree ofarticulation from the longitudinal axis of the shaft 23, thus providingan intuitive indication to the clinician. It will be appreciated thatother angular relationships may be selected.

The articulation control 13 includes a pair of mirrored articulationtransmission housings 204 that are attached to the housing cap 60.Moreover, the articulation transmission housing 204 includeslongitudinally aligned external tabs 206 that a clinician twists toeffect rotation of the articulation transmission housing 204, and thusof the end effector 12, about the longitudinal axis of the implementportion 22. The actuator lever 202 is attached to a cylindricalarticulation body 208 that resides within a cylindrical recess 210opening generally upward and perpendicular to the shaft 23. Thelowermost portion of the articulation body 208 includes prongs 212 thatsnap fit into an opening 214 in the articulation transmission housing208 near to the shaft 23, the prongs 212 preventing the articulationbody 208 from being withdrawn from the cylindrical recess 210.

Annularly presented gear teeth 216 are located about the lower portionof the articulation body 208 and mesh with teeth 218 on an articulationyoke 220. The articulation yoke 220 straddles an articulationrectangular window 222 formed in the closure sleeve 32. Closure sleeve32 is slidably moveable within the articulation control 13 (in thelongitudinal direction) to close and open the end effector 12. Thearticulation drive tube 200 moves longitudinally with the closure sleeve32 relative to the fixed articulation control 13. Window 222 providesclearance for a boss 224 inwardly presented from the articulation yoke220 that passes through the rectangular window 222 to engage a slot 226in the articulation drive tube 200, longitudinally positioning thearticulation drive tube 200 for rotational motion. The hollowarticulation drive tube 200 extends longitudinally within the closuresleeve 32 from the articulation mechanism 11 and terminates distallybefore the locking tabs 227 of the closure sleeve 32. The tabs 227 areinwardly bent behind the proximal face of the articulation drive tube200 and thereby retaining the articulation drive tube 200 in the shaft23.

It should be appreciated that the articulation transmission housing 204is operatively associated to the closure tube 35 of the shaft 23. Thehousing cap 60 retains the articulation yoke 220 in the articulationtransmission housing 204 and retains the articulation control 13 withinthe handle portion 20 by presenting proximally an outer diametercircular groove 228 that engages a circular inward lip 230 at the distalopening of the assembled base sections 50, 52.

FIGS. 10 and 11 depict the gear articulation mechanism 11 of FIGS. 1-2in the form of a spur gear articulation mechanism 240, which isgenerally the same as described above but with additional articulationdriving components on the other side of the articulation mechanism 240to thereby increase performance. Articulation mechanism 240 has arotatable hollow articulation drive tube 242 that is concentricallylocated within closure sleeve 32 and has a distally projecting gearsection 244 about a first circumference portion 246. Gear section 244meshes with a spur gear 248 attached to and proximally projecting fromclosure ring 250 which pivots about pins 253 extending through first andsecond pivot points 252, 260 projecting distally from the closure sleeve32. Thus, an articulation pivot axis passes through both the first andsecond pivot points 252, 260 and pins 253 rotatably couple closure ring250 to the closure sleeve 32. Rotation of drive 242 engages the gears242 and 248 and articulates closure ring 250 about first and secondpivot points 252, 260.

To increase the effective surface area of gear contact between thehollow articulation drive tube 242 and the closure ring 250, a secondcircumference portion 254 of the hollow articulation drive tube 242 hasa recessed distally projecting gear section 256 extending therefrom.Gear section 256 is operably coupled to a second spur gear 258 attachedto and proximally projecting from an opposite lateral side of theclosure ring 250 by a reversing gear 262 pivotally supported by theframe 34. Reversing gear 262 engages both the recessed distallyprojecting gear section 256 on one side and the second spur gear 258 ofthe closure ring 250 on the other.

When the closure trigger 26 is actuated, both the hollow articulationdrive tube 242 and pivotally attached closure tube 250 of the closuresleeve 32 are moved distally to close the anvil 18. The closure tube 35of the closure sleeve 32 is spaced away from the closure ring 33 bypivot points 252, 260 pinned to pivot holes 264 and 266 centered in spurgears 248, 258, and a frame opening 268 that extends therethrough. Theframe opening 268 provides clearance so that the proximal edges of theclosure ring 33 and the distal edges of the closure tube 35 of theclosure sleeve 32 do not collide during articulation.

FIG. 11 depicts in disassembled form an implement portion 270 thatincludes the spur gear articulation mechanism 240. A frame 272 islongitudinally attachable to the handle portion 20 (depicted in FIGS. 1and 2) with a bushing 274 on its proximal end for rotatingly engagementthereto. A frame trough 276 formed by an opening 278 longitudinallyaligned with the center of the frame 272 is longer than a firingconnector 280 that slides longitudinally within the frame trough 276.The proximal end of the firing connector 280 rotatingly engages thedistal end of the metal drive bar 140 (depicted in FIG. 6). The distalend of the firing connector 280 includes a slot 282 that receives aproximal end of the firing bar 14, attached therein by pins 284. A moredistal portion of the firing bar 14 is positioned within a lower groove286 in a firing bar slotted guide 288 that is distally engaged with anarticulating frame member 290 and the frame 272.

Articulating frame member 290 has a channel-anchoring member 292 thatdistally attaches to an attachment collar 294 of a proximal portion inthe elongate channel 16. The firing bar 14 passes through a lower slot295 in the articulating frame member 290. The articulating frame member290 is spaced away from the distal end of the frame 272 by the firingbar slotted guide 288 and flexibly attached thereto for articulation bya resilient connector 296. A widened proximal end 298 of the resilientconnector 296 engages a distally communicating top recess 300 in thedistal end of the frame 272 and a widened distal end 302 of theresilient connector 296 engages a proximally communicating top recess304 in the articulating frame member 290. Thereby, the elongate channel16 is attached to the handle portion 20, albeit with a flexible portiontherebetween.

The elongate channel 16 also has an anvil cam slot 306 that pivotallyreceives an anvil pivot 308 of the anvil 18. The closure ring 250 thatencompasses the articulating frame member 290 includes a distallypresented tab 310 that engages an anvil feature 312 proximate but distalto the anvil pivot 308 on the anvil 18 to thereby effect opening. Whenthe closure ring 250 is moved forward, its distally presented closingface 314 contacts a ramped cylindrical closing face 316, which is distalto tab 312 of the anvil 18. This camming action closes the anvil 18downward until the closing face 314 of the closure ring 250 contacts aflat cylindrical face 318 of the anvil 18.

SUPPORT PLATES

FIGS. 12-13 depict the articulation mechanism 240 along the articulationpivot axis illustrating flexible support structures between the shaft 23and the end effector 12 and a construction of the firing bar 14 thatadvantageously performs severing yet is flexible enough forarticulation. The hollow articulation drive tube 242 engages the spurgear 248 of the closure ring 33. Omitted from this view are the proximalportion 35 of the closure sleeve 32 (i.e., closure tube 35) thatlongitudinally positions for articulation the spur gear 248 at an upperpivot point 252 and the lower pivot point 260.

Resilient support in the articulation mechanism 240 allow articulationabout the articulation pivot axis includes a pair of support plates 400,402 that flank a proximal portion of the firing bar 14 to preventbuckling as they pass through the frame opening 268. Thus, the firingbar 14 is capable of transferring large loads while being flexible. Thisproximal portion of the firing bar 14 is depicted as an elongate taperedfiring strip 404 formed as one or more flat blades of spring materialthat are aligned for flexing about the articulation pivot axis. Thistapered firing strip 404 transitioned to a thicker distal portion,depicted as a firing bar head 406, that includes the cutting edge 48,upper pin 38, middle pin 46 and firing bar cap 44 (pins omitted in FIG.12). This thicker firing bar head 406 has increased thickness to resistdeflection during firing, thereby ensuring an effective severing andactuation of the staple cartridge 37. The support plates 400, 402advantageously mitigate the effects of peak firing loads in the taperedfiring strip 404 by introducing a yielding engagement of one or both ofthe proximal and distal sides 408, 410 of the articulation mechanism240.

The pair of support plates 400, 402 each have a proximal and distalsliding spring ends 412, 414, received respectively by a frame pocket416 in the frame 32 and an end frame pocket 418 in the articulatingframe member 290. These pockets 416, 418 provide clearance for thespring ends 412, 414 of the support plates 400, 402 as the articulationmechanism 240 articulates, lessening the frame opening 268 toward theinside and lengthening the frame opening 268 toward the outside.Reversing the direction of articulation of the end effector 12 reverseslocation of the spring ends 412, 414 (not shown). Insofar as theproximal spring ends 412 tend not to be rigidly engaged to a distalextreme surface 420 of the frame pocket 416, the support plates 400, 402are able to yieldingly move distally in response to a peak firing loadin the firing bar 14.

RETAINING BARS IN ARTICULATING MECHANISM

FIGS. 14-15 depict an articulation mechanism 500 that advantageouslyprevents pinching between the support plates 400, 402 of a firing bar 14within an implement portion 22 similar to that described for FIG. 11. Inaddition, instead of the spur gear connection of the articulationmechanism described above, FIG. 14 depicts a bevel gear section 502 isdistally attached to an articulation drive tube 504. A closure ring 506includes a bevelgear 508. The closure ring 506 couples to the anvil 18.The closure tube (not depicted) encompasses a frame 510 and pivotallyconnects to the closure ring 506. An articulating frame member 512attaches to the elongate channel 16 that receives the staple cartridge37. The firing bar 14 is proximally attached to the firing connector 280and longitudinally translates as previously described.

With reference to FIGS. 14-15, the support plates 400, 402 flexiblyconnects and spaces apart the distal end of the frame 510 and thearticulating frame member 512 instead of a resilient connector 296 (seeFIG. 11). Additional resilient connection is advantageously provided byretaining bars 514 that rest upon the firing bar 14. The lateralthickness of each retaining bar 514 is thin enough to flexappropriately, with a sufficient number of retaining bars 514 tolaterally space the support plates 400, 402 so that the underlyingfiring bar 14 is not pinched upon articulation of the articulationmechanism 500. Each retaining bar 514 includes a distal and proximallateral tab 516, 518 that upwardly engage respectively a distal recess520 in the articulating frame member 512 and a proximal recess 522 inthe frame 510.

While the present invention has been illustrated by description ofseveral embodiments and while the illustrative embodiments have beendescribed in considerable detail, it is not the intention of theapplicant to restrict or in any way limit the scope of the appendedclaims to such detail. Additional advantages and modifications mayreadily appear to those skilled in the art.

The present invention has been discussed in terms of endoscopicprocedures and apparatus. However, use herein of terms such as“endoscopic”, should not be construed to limit the present invention toa surgical stapling and severing instrument for use only in conjunctionwith an endoscopic tube (i.e., trocar). On the contrary, it is believedthat the present invention may find use in any procedure where access islimited to a small incision, including but not limited to laparoscopicprocedures, as well as open procedures.

For another example, although the E-beam firing beam 14 has advantagesfor an endoscopically employed surgical severing and stapling instrument10, a similar E-Beam may be used in other clinical procedures. It isgenerally accepted that endoscopic procedures are more common thanlaparoscopic procedures. Accordingly, the present invention has beendiscussed in terms of endoscopic procedures and apparatus. However, useherein of terms such as “endoscopic”, should not be construed to limitthe present invention to a surgical stapling and severing instrument foruse only in conjunction with an endoscopic tube (i.e., trocar). On thecontrary, it is believed that the present invention may find use in anyprocedure where access is limited to a small incision, including but notlimited to laparoscopic procedures, as well as open procedures.

For yet another example, although an illustrative handle portion 20described herein is manually operated by a clinician, it is consistentwith aspects of the invention for some or all of the functions of ahandle portion to be powered (e.g., pneumatic, hydraulic,electromechanical, ultrasonic, etc.). Furthermore, controls of each ofthese functions may be manually presented on a handle portion or beremotely controlled (e.g., wireless remote, automated remote console,etc.).

As yet an additional example, although a simultaneous stapling andsevering instrument is advantageously illustrated herein, it would beconsistent with aspects of the invention supporting a firing mechanismthrough an articulating shaft with other types of end effectors, such ascutters, staplers, clip applier, access device, drug/gene therapydelivery device, and a energy device using ultrasound, RF, laser, etc.

For example, various combinations of rigidly attached, resilientlyattached, and springedly attached support plate ends may be used, suchas resilient attached proximal end and a springedly attached distal end.

What is claimed is:
 1. A surgical instrument, comprising: a handleportion operably configured to produce an articulation motion and afiring motion; a shaft having a longitudinal axis attached to the handleportion for transferring the articulation motion and the firing motion;an articulation mechanism coupling the shaft to the end effector andresponsive to the articulation motion to rotate the end effector fromthe longitudinal axis of the shaft; an end effector distally attached tothe articulation mechanism; a firing mechanism responsive to the firingmotion and coupled for movement through the articulation mechanism andend effector in response to the firing motion; a pair of support platesflanking the firing mechanism across the articulation mechanism; and aretaining member inserted between and laterally spacing the pair ofsupport plates proximal to the firing mechanism for spacing the pair ofsupport plates at least a thickness of the firing mechanismtherebetween.
 2. The surgical instrument of claim 1, wherein theretaining member comprises a plurality of laterally stacked retainingbars.
 3. A surgical instrument comprising: a handle portion operable toproduce a firing motion, a closing motion, and an articulation motion; ashaft coupled to the handle portion operable to separately transfer thefiring motion, the closing motion, and the articulation motion; anelongate channel coupled to the shaft; an anvil pivotally coupled to theelongate channel, responsive to the closing motion from the shaft; afiring device including a distally presented cutting edge longitudinallyreceived between the elongate channel and the anvil; an articulationmechanism pivoting the elongate channel from the shaft in response tothe articulation motion; and a pair of support plates flanking thefiring mechanism across the articulation mechanism; and a retainingmember inserted between and laterally spacing the pair of support platesproximal to the firing mechanism.
 4. The surgical instrument of claim 3,wherein the retaining member comprises a plurality of laterally stackedretaining bars.